Apparatus and method for testing liquid crystal display panel

Abstract

A device and a method for testing a liquid crystal display panel are disclosed in the present invention, which enable to conveniently inspect a cutting plane of an individual unit liquid crystal panel. The apparatus includes a first memory unit storing a reference image of an end portion of a reference panel taken through a camera, a second memory unit storing an observed image of an end portion of a cut unit liquid crystal display panel taken through the camera, a comparison/computation unit computing a difference value by comparing the reference image and the observed image, and a display unit displaying the difference value of the comparison/computation unit.

What is claimed is: 
     
       1. An apparatus for testing a liquid crystal display panel, comprising:
 a first memory unit storing a reference image of an end portion of a reference panel taken through a camera; 
 a second memory unit storing an observed image of an end portion of a cut unit liquid crystal display panel taken through the camera; 
 a comparison/computation unit computing a difference value by comparing the reference image and the observed image; and 
 a display unit displaying the difference value of the comparison/computation unit. 
 
     
     
       2. The apparatus of  claim 1 , wherein the camera is a charge coupled device (CCD) camera. 
     
     
       3. The apparatus of  claim 1 , wherein each of the reference panel and the cut unit liquid crystal display panel has an aligning mark at a corner. 
     
     
       4. The apparatus of  claim 1 , wherein the second memory unit additionally stores a moving distance of the camera to display through the display unit. 
     
     
       5. The apparatus of  claim 1 , wherein the difference value is a positive (+) number when a burr appears on the observed image. 
     
     
       6. The apparatus of  claim 1 , wherein the difference value is a negative (−) number when a recess appears on the observed image. 
     
     
       7. A method of testing a liquid crystal display panel, comprising:
 photographing a reference image at an end portion of a reference panel; 
 photographing an observed image at an end portion of a testing liquid crystal display panel; 
 computing a difference value by comparing the reference image and the observed image; and 
 displaying the difference value. 
 
     
     
       8. The method of  claim 7 , wherein the photographing the reference image includes:
 aligning the reference panel with a camera through an aligning mark at a corner of the reference panel; and 
 obtaining the reference image by scanning the camera along an edge of the reference panel to photograph the end portion of the reference panel. 
 
     
     
       9. The method of  claim 7 , wherein the photographing the observed image includes:
 aligning the testing liquid crystal display panel with the camera through an aligning mark at a corner of the testing liquid crystal display panel; and 
 obtaining the observed image by scanning the camera along an edge of the testing liquid crystal display panel to photograph the end portion of the unit liquid crystal display panel. 
 
     
     
       10. The method of  claim 7 , wherein the difference value is expressed by a positive (+) number when a burr appears on the observed image and a negative (−) number when a recess appears on the observed image. 
     
     
       11. The method of  claim 7 , wherein the photographing the observed image along the end portion of the liquid crystal display panel is carried out by displaying measured lengths of longer and shorter sides of the testing liquid crystal display panel through a moving distance of the camera. 
     
     
       12. A method of testing a liquid crystal display panel, comprising:
 bonding first and second substrates to each other; 
 cutting the bonded first and second substrates into a plurality of unit liquid crystal display panels; 
 photographing an observed image of an end portion of each of the unit liquid crystal display panels through a camera; 
 computing a difference value by comparing the observed image to a reference image of an end portion of a reference panel; and 
 displaying the difference value. 
 
     
     
       13. The method of  claim 12 , further comprising forming a liquid crystal layer after bonding the first and second substrates to each other. 
     
     
       14. The method of  claim 12 , further comprising forming a liquid crystal layer by dropping liquid crystals on one of the first and second substrates before bonding the first and second substrates to each other. 
     
     
       15. The method of  claim 12 , wherein the difference value between the observed image and the reference image indicates information on a cutting plane of each of the unit liquid crystal display panels. 
     
     
       16. The method of  claim 15 , wherein the difference value is a positive (+) number when the cutting plane has a burr. 
     
     
       17. The method of  claim 15 , wherein the difference value is a negative (−) number when the cutting plane has a recess.